javascript (window).unload in not working for certain chrome versions

Question

The following method of window.unload works fine on different browsers and some browsers of chrome as well but does not work on particular chrome browsers.

$(window).unload(function () {  
    var tabSessionId = getUrlVars()["info"];    
    var ajurl = "/hello/help";
    $.ajax({
        type: "GET",
        data: { 'info': info},
        url: ajurl,
        async: false,
        error: function (xhr, status, error) {
            // alert('error');
        },
        success: function () {
            // alert('Data Saved:');
        }
    });
});

I read that this is an unstable method so tried $(window).bind('beforeunload', function() and $(window).('beforeunload', function() as well but it still did not work. Please help as I am stuck on this since a long time.

Edit 1 - After adding console.log, it is observed that the unload method is called but it is reaching the error method of ajax call. After updating async to true, no logs get printed. I had added logs in the place where alerts are commented.

Edit 2 : Fetch method used instead of ajax call -

  fetch("/hello/help?info=“ + encodeURIComponent(info))
  .then(res => res.json())
  .then(res => {
    console.log(“success”);
    console.log(res);
  })
  .catch(error => {
    console.log(“ in error method”);
    console.error(error);
  });

Error received in fetch - Failed to fetch

Error received in ajax - VM307 GuidedHelp.js:300 Error NetworkError: Failed to execute 'send' on 'XMLHttpRequest': Failed to load Synchronous XHR in page dismissal. See https://www.chromestatus.com/feature/4664843055398912 for more details.

Can someone let me know if the fetch method code correct or is there any mistake?